Migrating from SQL Server to Postgres
The migration tool does not support switching between DB vendors.
It's not what it's used for.
The migration tool updates the database schema from one version of Bonita to another. It is not made to port a database from one Db vendor to another.
There is no easy way to do what you are trying to do. My best guess will be to manually create a dump of your SQLServer database and then try to import it into your Postgres local installation.
If it works, you then change your database.properties in your Bonita bundle to connect to your postgres database.
Thank you for your help danila.mazour_2.
Will try soon to do it manually as you said. Will update if I succeed.